Pliers-type hand tool



April 18, 1967 C. C. SCHMIDT PLIERS-TYPE HAND TOOL Filed June 25, 1965 'IIVII'I'I 1111001.

I30 I36 I40 I32 INVENTOR.

CHARLES C. SCHMIDT ATTORNEY United States Patent 3,314,319 PLIERS-TYPE HAND TOOL Charles C. Schmidt, 3126 Arnold, Topeka, Kans. 66614 Filed June 25, 1965, Ser. No. 466,911 7 Claims. (Cl. 81-367) The present invention relates to new and useful improvements in pliers-like hand tools, and more particularly pertains to such a tool wherein pivotally connected jaws are provided with opposed blades that are elongated in the direction of the pivotal axis and which terminate at their free ends in substantially straight edges that are parallel to the pivotal axis, with means being provided to maintain such spaced edges spaced from each other.

One of the principal objects of the invention is to provide a hand tool such that blades carried by the jaws of such tool may be inserted under the drive edges of adjacent duct work sections, whereby such sections may be drawn into sufficiently close proximity that a drive cleat can be secured about such drive edges, all in such a manner that the drive edges are not deformed excessively and so that the bight portions are not forced together with excessive force such that might cause cutting thereof by the blades, or any twisting or misalignment due to any looseness or play that might develop with wear in the pivotal connection in the jaws.

Another important object of the invention is to provide a tool of the character specified in the preceding paragraph which may be operated to place the blades in a releasably fixed spatial relationship with respect to each other such that the blades and supporting jaw structure can be employed as a specially shaped tool that may be struck by a hammer or the like to engage an end of a drive cleat and drive the same out of engagement with the drive edges of adjacent duct sections.

It is another important object of the invention to provide a tool of the character above which not only will serve to force adjacent ends of duct work sections into position for securance by a drive cleat without damaging the drive edges, but which will tend to correct minor irregularities or imperfections in the drive edges that might otherwise interfere with placement of the drive cleat.

Another important object of the invention is to provide a tool of the character specified above which will serve on manual manipulation thereof to place adjacent sections of duct work into position so that the drive edges thereof can be secured by a drive cleat, but additionally, to provide such a tool that will releasably lock in a position holding properly positioned duct work sections so as to not require manually holding by the worker whereby both the hands of the worker are free to place and drive a drive cleat into duct section securing position.

Still another important object of the invention is to provide a pliers-like hand tool such that work engaging elements of the jaws can only be forced to a selectively adjustable spaced relationship to each other.

Yet another important object of the invention is to provide a pliers-like hand tool of the character specified in the immediately preceding paragraph such that when the work engaging elements of the jaws have been driven forcibly into such selected spaced relationship that the work engaging elements are not subject to being displaced further from each other solely upon an application of force exerted between such work engaging elements, whereby such hand tool, depending upon the character of the work engaging elements selected therefor, can, for example, constitute a wrench of selectively fixed size.

One broad aspect of the invention involves in a toggletype gripping device of the class including pivotally connected jaws having coacting work engaging elements, and handles connected by toggle link means for releasably securing the jaws against moving from each other when the jaws are loaded against an object gripped between the work engaging elements; the combination therewith of said jaws being provided with stop means spaced from said work engaging elements for positively limiting closure of the jaws to constitute a gripping load for the jaws. From a more limited standpoint, such stop means is adjustable in position and can for example be threaded through one of the jaws to adjustably extend toward the other jaw so as to adjustably limit the extent that the jaws and the work engaging elements thereof can move toward each other.

Another aspect of the invention involves structure such as specified in the last two paragraphs wherein each of the jaws is elongated in the direction of the pivotal axis of the pivotal connection of the jaws, and each of the jaws includes a substantially flat blade at its extremity most remote from the pivotal axis that extends toward the blade of the other jaw with the blade terminating in a free edge that is substantially straight and parallel to the pivotal axis, whereby the blades can be engaged under the drive edges of adjacent sections of duct work and brought to bear against the bight portions of such adjacent sections to bring the latter into position for securance by a drive cleat.

Another aspect of the invention involves the provision of an improved pliers-like hand tool for use in connection with duct work of the type wherein the drive edges of adjacent sections of duct are secured by a drive cleat, said tool comprising a pair of jaws pivotally connected about a pivotal axis, a pair of handles connected to the jaws for urging the jaws toward each other on manually gripping the handles, each of said jaws being elongated in the direction of the pivotal axis and including a substantially flat blade at its extremity most remote from the pivotal axis that extends toward the blade of the other jaw with said blade terminating in a free edge that is substantially straight and parallel to the pivotal axis, and stop means carried by one of the jaws in spaced relation to the blades for engaging the other jaw and limiting closure of the jaws to a value such that the free edges of the blades remain spaced. From a narrower standpoint such tool additionally involves each of the jaws including a second blade spaced from and parallel to the first mentioned blade thereon, whereby a drive edge can be received therebetween.

An important feature of the invention resides in the provision of a threaded stop threadingly extending through one jaw of a pliers-like hand tool so as to adjustably limit the approach of work engaging elements of jaws toward each other. Such feature when applied to a toggle-type hand tool serving to constitute a load against which the toggle link can be actuated beyond its dead center position so as to prevent separation of the jaws from the limiting position by application of force applied betwen the jaws in a direction such as to tend to open the latter.

Another important feature of the invention is the provision of a pair of spaced blades on each of the jaws of a pliers-like hand tool such that the drive edges of ada jacent sections of duct work can be engaged between the pairs of blades carried by each of the jaws.

Other objects, aspects and features of the invention will become apparent during the ensuing description of a preferred embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a side elevational view of the tool, with certain concealed portions thereof being shown in dashed outline;

FIGURE 2 is a top plan view of the tool shown in FIGURE 1, certain concealed portions thereof being shown in dashed outline;

FIGURE 3 is an end view of the tool shown in FIG- URES l and 2, this vie-w being taken from the jaw end of the tool, and with certain concealed portions thereof being shown in dashed outline;

FIGURE 4 is an enlarged fragmentary sectional detail view of the manner in which adjacent duct work sections and the drive edges thereof are arranged prior to securance by a drive cleat;

FIGURE 5 is a View similar to that shown in FIGURE 4 together with a fragmentary sectional detail view of the relationship of the blades of the jaws to the drive edges when the tool is being employed to either force the adjacent duct work sections together, or when the tool is being used for driving a drive cleat endwise from a position interlocked therewith; and

FIGURE 6 is an enlarged fragmentary detail sectional view showing a drive cleat in position interlocked with the drive edges of and holding adjacent duct work sections in assembled relation.

Referring now to the drawings, wherein like numerals designate like parts throughout the various views, the reference numeral 10 designates the tool of the invention generally, which in its preferred form includes a toggletype gripping device construction designated generally at 12.

The toggle-type gripping device 12 is well known in the art and the specific form thereof shown in the drawings is exemplary of many forms in which such basic structure has been manufactured and sold in large numbers for quite a number of years. For a full understanding of the structural principles involved in toggle-type gripping devices such as may be employed in the practice of the present invention, reference is made to US. Patents Nos. 2,280,005, 2,514,130, and 2,803,320.

Briefly, a toggle-type gripping device such as that indicated at 12 in the drawings comprises a fixed jaw 14 to which a pivoted jaw 16 is pivotally connected to the fixed jaw 14 upon a pivotal axis that is perpendicular to the plane of FIGURE 1 by a pivot pin 18 having upset ends 20 and 22 so as to be in the nature of a rivet for retaining the jaws 14 and 16 in assembled relationship.

The fixed jaw 14 is integral with a handle 24, and the pivoted jaw 16 has pivotally connected thereto a pivoted handle 26, the pivoted connection between the jaw 16 and the handle 26 being by means of a rivet-like pivot pin 28.

The handles 24 and 26 are connected by means of a toggle link 30 having one end pivotally connected by a rivet-like pivot pin 32 to the handle 26, and having its other end abutting the inner end 34 of an adjustment screw 36 that is threaded into the end of the handle 24 remote from the jaw 14. Means, not shown, is conven- :ionally provided to guidingly restrain the end 38 of the :oggle-link 30 adjacent the end 34 of the screw 36 in alignment with the latter.

The arrangement is such that for a given endwise adustment of the screw 36 in the handle 24, manual grip- )ing of the handles 24 and 26 to urge the latter toward :ach other will, assuming the end 38 of the toggle link F0 to remain in constant abutting relationship to the end $4 of the screw 36, cause pivotal movement of the jaw 6 towards the fixed jaw 14 as well as movement (as seen n FIGURE 1) of the pivot pin 32 from a position below a line passing through the pivot 28 and the end 34 of the screw 36 to a position precisely on such line. The geometry is such that as the pivot pin 32 approaches such line the rate of movement of the pivot pin 32 greatly exceeds that of the relative movement of the jaws-14 and 16, whereby great mechanical advantage is obtained. When the pivot pin 32 is precisely on a straight line extending through the pivot pin 28 and the position of fulcrum-like abutment of the end 38 of the toggle link 30 against the handle 24 and the end 34 of the screw 36 constitues a dead center position for the toggle link 30, and corresponds to the nearest approach of the jaws 14 and 16 toward each other for a given setting of the screw 36.

A further closing movement of the handles 24 and 26 results in the pivot pin 32 moving upwards past its dead center position, it being noted that such upward displacement of the pivot pin 32 above its dead center position is limited by virtue of a lateral lobe 40 on the toggle link 30 coming into limiting engagement with a part of the structure of the handle 26. The movement of the pivot pin 32 upwards above its dead center position is so slight that only a very minor degree of opening movement of the jaws 14 and 16 occurs during such upward movement. With the lobe 40 of the toggle link 30 in engagement with a part of the structure of the handle 26 and the pivot pin 32 being displaced upwardly from its dead center position, it will be seen that opening of the jaws 14 and 16 by force applied directly therebetween is impossible except to the extent permitted by resilience of the parts and barring such force reaching destructive magnitude.

Thus, the structure of the toggle-type gripping device 12 serves to enable in the ordinary usage of the same the placement of an object between the jaws 14 and 16 and the application of a very strong gripping force thereon by the jaws 14 and 16 by manually gripping the handles 24 and 26 together, and when the position of the screw 36 has been appropriately preselected in relation to the size of the object gripped, the pivot pin 32 will pass to its limited position slightly above dead center, whereby the device will firmly grip the object with only very slightly diminished gripping force, and the handles 24 and 26 will remain in the gripping position without the necessity for holding thereof by the user. The resilience of the subject gripped coupled in any event with the resilience of the structure of the device 12 will serve to maintain the object tightly gripped (it being understood that the device 12 is made of steel possessing an inherent degree of resilience.) Indeed, ordinarily, the object may be gripped so tightly when the device 12 is so applied that considerable difiiculty in releasing the same is encountered if such release is sought to be accomplished by unscrewing the screw 36, or even if such release is sought to be accomplished by attempting to spread the handles 24 and 26 apart. In view of such release difiiculties, it is preferred, as is conventional, that the handle 26 be provided with a release lever 42 pivoted to the handle 26 at 44 in such an arrangement that squeezing the ends 46 and 48 of the lever 42 and the handle 26, respectively, together causes an end 50 of the lever 42 to bear against the lobe 40 of the toggle link 30 and thereby move the pivot pin 32 downwardly through its dead center position and thus free the handles 24 and 26 and the jaws 14 and 16 for corresponding separating movements.

Conventional devices of the character indicated at 12 include a coiled tension spring such as indicated at 52 for yieldingly urging opening movement of the jaws 14 and 16 such that when the pivot pin 32 is below its dead center position the jaws 14 and 16 as well as the handles 24 and 26' are held apart for convenient insertion of an object between the jaws 14 and 16, and so that a squeezing pressure is all that a user must apply manually to the handles 24 and 26.

The structure thus far described in detail is entirely conventional in character, and as thus far described in detail does not in and of itself constitute the subject invention.

According to the present invention, means is provided in combination with and as a component of the gripping device 12 in order to provide a gripping load for the jaws 14 and 16 so as to maintain the jaws 14 and 16 in a fixed relationship to each other when the pivot pin 32 is positioned above its dead center position, whereby the device 12 can effectively constitute a rigid tool carrying in relatively fixed relationship whatever character of work engaging elements it may be desired to aifix to the jaws 14 and 16. Such means is preferably in the form of an adjustable stop comprised of a threaded post or screw 60 that is threaded through the jaw 14 directly toward the jaw 16, with the screw 60 being disposed in the jaw 14 at a position in alignment with the longitudinal extent of the handle 24. The outer or upper end of the threaded post or screw 60 is provided with a knurled knob 62 fixed thereto, whereby the lower blunt end 64 of the screw 60 can be set to adjustably limit the approach of work engaging elements on closing movement of the jaws 14 and 16.

Before proceeding to consider any specific character of work engaging elements that may be fixed to the jaws 14 and 16, the use of the stop means described above will be first explained. Initially, adjustment in the position of the screw 60 is first made by turning the knob 62 to a position such that the jaws 14 and 16 will have the desired fixed spacing when the blunt lower end 64 of the screw 60 abuts the post 66 is made. At this time, that is, while the screw 60 and the post 66 are in abutting relationship, it is usually most convenient to adjust the screw 36 by turning the same to move inwardly of the handle 24 until firm resistance is encountered, and thereafter to open the jaws 14 and 16 and screw the screw 36 a short additional interval inwardly into the handle 24, the object being so that a very strong squeezing or gripping force must be exerted on the handles 24 and 26 after the threaded post 60 and the post 66 are in engagement in order to cause sufiicient fiexure due to resilience of the parts involved in order to move the pivot pin 32 upwardly of dead center position as viewed in FIGURE 1, inasmuch as when such position and stress of the parts is achieved, the bearing pressure exerted between the abutting posts 60 and 66 will cause a resulating force against the toggle link 30 of such character as to maintain the togle lever or link 30 in locking position in which the pivot pin 32 is disposed upwardly of its dead center position as viewed in FIGURE 1. Needless, to say, the abuting engagement of the posts 60 and 66 prevents the jaws 14 and 16 moving into closer proximity to each other, and the aforesaid locking position of the toggle link 30 prevents movement of the jaws 14 and 16 away from each other insofar as exertion of any force between the jaws 14 and 16 in such a direction such as to tend to cause opening of the jaws. Accordingly, with the tool in such a condition, the same is essentially a rigid tool that will remain rigid until released by either unscrewing the screw 36, forcibly spreading the handles 24 and 26 apart, or by use of the release lever 42 as described previously for releasing the toggle link 30.

It will be appreciated by those skilled in the art that if it were not for the provision of the stop means comprised of the posts 60 and 66, the jaws 14 and 16 would not have the pressure exerted therebetween by such posts 60 and 66 so as to tend to hold the toggle link 30 in locking position, but additionally, the jaws 14 and 16 could be moved into closer proximity to each other with only the small force necessary to extend the spring 52 slightly, whereupon the toggle link is perfectly free to move so that the pivot pin 32 falls below its dead center position (as seen in FIGURE 1), and any subsequent application of pressure between the jaws 14 and 16 tend- 6 ing to separate the latter will indeed cause full separation of the jaws 14 and 16.

Those familiar with the art will, of course, understand that with the device in the fixed condition enabled by the provision of the stop means constituted of the posts 60 and 66 can include any sort of work engaging elements on the jaws 14 and 16 that may be desired, whereby the tool can be made to comprise a fixed wrench of a size preselected by adjustment of the screw 60, etc. For example, though not specifically shown, the work engaging elements could simply comprise opposed faces on the jaws 14 and 16 outwardly spaced from the stop means on the side opposite from the pivot pin 18, the spacing of which would be determined by the adjustment of the post 60, and with the tool clamped tightly with the posts 60 and 66 in abutment and the toggle link 30 in locking position, such opposed work engaging element faces could be spaced to constitute etfectively an open ended fixed wrench that could be turned either clockwise or anticlockwise simply by applying a torque through only one of the handles 24 or 26 in the appropriate direction. For instance such opposed :faces could be adjusted to be fixed at a spacing of slightly in excess of 95 of an inch and the tool applied repeatedly to a W inch nut or bolt to turn the latter without the operator or user of the tool having to repeatedly make appropriate adjustment of the handles 24 and 26 to secure appropriate engagement nor would he be required to maintain a gripping pressure upon the handles 24 and 26 when applying a turning torque.

As a preferred example of work engaging elements that may be secured to the jaws 14 and 16 outwardly from the stop means constituted of the post 60 and 66 from the pivot pin 18 is the special form of work engaging elements or devices designated at 70 and 72 in FIGURES 1 through 3. The special work engaging element 70 is fixed rigidly, as by welding or the like 74 to the face of the jaw 14 that opposes the jaw 16. The ele ment 70 is substantially elongated in the direction of the pivotal axis of the pivotal pin 18, and the conventional gripping device structure 12 is centered with respect thereto as clearly shown in FIGURES 2 and 3.

As best shown in FIGURE '1, the device 70 comprises a steel plate 76 that extends forwardly from the jaw 14, and thence upwardly and forwardly at 78 to terminate in a iforwardly extending portion 80 that terminates along a line 82 that is parallel to the axis of the pivot pin 18. It will be noted that the threaded opening 84 in the jaw 14 through which the threaded post 60 extends also extends through the portion of the plate 76 directly underlying the jaw 14. It is preferred that the forwardly projecting portion of the plate 76 have lateral edges that are forwardly divergent as indicated at 86 and 88.

The work engaging element 72 is generally similar to the work engaging element 70 and comprises a steel plate having a forwardly extending portion 90 that is fixedly secured to the jaw 16 as by welding or the like 92, with the plate extending forwardly and downwardly at 94 to terminate in a forwardly extending plate portion 96 having a free or remote edge 98 that is parallel to the pivotal axis of the pivot pin 18. The plate portion 80 and 96, as clearly apparent on inspection of FIGURE 1, are spaced a substantial distance apart by virtue of the upwardly and downwardly inclined portions 78 and 94 of the plates, and can assume a substantially parallel relationship when the portions 76 and 90 of the plates are spaced apart by the posts 60 and 66, it being noted that the post 66 is rigidly fixed tothe plate portion 90 and to the jaw 16.

In the preferred construction, the structures of the work engaging elements 70 and 72 as thus far described are essentially mirror images of each other and are disposed in a relationship with respect to each other and the remaining portions of the tool 10 so as to be approximately symmetrical with respect to a plane passing therebetween and including the pivotal axis of the pivot pin 18. In any event, the work engaging elements 70 and 72 are coextensive with respect to their longitudinal extents parallel to the pivotal axis of the pivot pin 18.

At their remote or outermost extremities, the plate portions 80 and 96 are provided with blades 100 and 102 that are integral therewith, each of the blades 100 and 102 extending towards the other and terminating in edges 104 and 106, respectively, that are each parallel to the pivotal axis of the pivot pin 18. As Will be clearly shown in FIGURE '1, the blades 100 and 102 are substantially flat and are so arranged as to be essentially coplanar when the edges 104 and 106 thereof are in close proximity to each other. Preferably, the edges 104 and 106 are beveled at 108 and 110, respectively, so that such edges are of substantially sharpened aspect.

Although not essential, it is strongly preferred that each of the elements 70 and 72 be provided with'additional integral blades 112 and 114, respectively, which terminate in beveled edges 116 and 118, it being noted that the edges of the blades 100 and 102 are beveled in a direction opposite to that of the bevel of the edges of the blades 1.12 and 114. The blades 112 and 114 are coextensive longitudinally with the blades 100 and 102, are parallel to such blades and are spaced therefrom for a purpose subsequently to become apparent. Before proceeding to a description of the uses of the improved tool 10, it is to be noted with respect to FIGURE 1 that the blades 112 and 114 extend towards each other to the same extent that the blades 100 and 102 extend towards each other. It is also to be noted that although the blades 100 and 112 are shown as 'being in edge contact with the blades 102 and 114 when the gripping device 12 is in such condition that the threaded post 60 engages the post 66 and the toggle link 30 in its locking position, the blades will in the use of the tool normally be spaced apart for an interval of about twice the spacing of the blades i100 and 112 when the posts 60 and 66 are in abutting relationship, though such spacing may be lesser or greater if desired. Finally, before proceeding with the description of uses of the tool 10, it should be noted on the inspection of FIGURE 3 that all the blades 100, 102, 112 and 114 terminate longitudinally in planes designated at 120 and 122 in FIGURE 3, such planes being normal or perpendicular to the pivotal axis of the pivot pin 18.

The use of the improved tool will be best appreciated upon reference to FIGURES 4, 5 and 6. FIG- URE 4 shows adjacent sections of duct work at 130 and 132, the duct work section 130 being bent to have a portion thereof constituting a drive edge 134 connected thereto by a bight portion 136, it being noted that the drive edge 134 is essentially parallel to the principal extent of the duct work section 130. Similarly, the duct Work section 132 includes a drive edge 138 connected thereto by a bight portion 140. The drive edges 134 and 138 constitute a means for use in securing the duct work sections 130 and 132 together by means of a drive cleat. It will be appreciated on inspection of FIGURE 4 that the duct work sections 130 and 132 are shown in such relationship with respect to each other that a drive cleat may be applied thereto.

FIGURE 6 shows the duct work sections 130 and 132 secured together by means of a C-shaped drive cleat 142. As clearly shown in FIGURE 6, the drive cleat 132 includes a web portion 144 that overlies the drive edges 134 and 138 of the duct work sections 130 and 132 and has inturned edges or legs 146 and 148 embracing the drive edges 134 and 138, respectively, so as to be disposed in the spaces between such drive edges and their respective duct work sections 130 and 132. The drive cleat 142 is applied to duct work sections arranged as shown in FIG- URE 4 by first arranging the duct work sections in such a. manner and then driving the drive cleat 142 endwise to secure the entire marginal extent of the duct work sections 130 and 132 together.

The improved tool 10 is employed in one form of use thereof to draw duct work sections into the relationship thereof shown in FIGURE 4, it being understood that it frequently occurs that considerable pressure must initially be exerted to draw the two adjacent ends of the duct work section into the relationship shown in FIGURE 4, and it is also usually necessary to hold the duct work sections at such relationship while the drive cleat is positioned to be driven and while it is driven into the assembled position shown in FIGURE 6. The improved tool 10 is employed for this use by initially adjusting the screw 60 so that the blades and 102 are spaced apart on looking the toggle link 30 an interval corresponding approximately to the spacing of the inner curvatures of the bight portions 136 and 140 as shown in FIG- URE 4. The jaws 14 and 16 are then opened to an extent sufiicient that the drive edge 134 can be received between the blades 100 and 112 with the drive edge 138 being received between the blades 102 and 114, whereupon the handles 24 and 26 are firmly gripped together until the posts 60 and 66 come into abutting engagement and the toggle link 30 forced into locking position. It will be noted that the beveled edges of the blades facilitate such insertion and may during application of gripping pressure serve to straighten out minor irregularities or ripples along the extents of the drive edges 134 and 138 along the extent of the juncture between the duct work sections and 132. When the handles 24 and 26 have been gripped together sufficiently to lock the gripping device 12, the duct work sections 130 and 132 will have been forced into the relationship shown in FIGURE 4, and the user of the tool 10 can release the handles 24 and 26 and the tool 10 will remain in operative engagement with the duct work sections 130 and 132 to maintain them in the desired relationship. Thus, with the operators hands free to do so, he can properly position for driving and proceed with driving of the drive cleat 142.

If the juncture of the duct work sections 130 and 132 is substantially elongated, the tool 10 can be successively applied along the length of such juncture with the drive cleat 142 being driven an additional distance between each successive repositioning of the tool 10.

It will be appreciated that as soon as the drive cleat 142 has been driven as far as can be accomplished with the tool 10 being applied at one position along the length of the juncture of the duct work sections 130 and 132 as is possible, the tool 10 can be readily released from the duct work sections 130 and 132 by use of the release lever 46, and the blades disengaged from the drive edges 134 and 138.

From the foregoing it will be appreciated that it is not essential that the work engaging elements 70 and 72 include the blades 112 and 114; however, it will also be appreciated that the provision of such additional blades 112 and 114 materially contribute to straightening rip pled or bent drive edges as well as aiding in preventing inadvertent bending or rippling of such edges during application of the tool 10.

It will be understood by those skilled in the art that it is not essential that the tool 10 include provision of stop means such as comprised of the adjustable screw 60 and the abutment post 66, and that the function of the latter can be largely assumed by the edges 104 and 106 simply engaging and gripping the bight portions 136 and therebetween, in which case the jaws l4 and 16 can be furnished with a gripping load with the toggle link 30 in its locking position, that is, the pivot pin 32 displaced above, as seen in FIGURE 1, a line connecting the pivot pin 28 and the end 34 of the screw 36. Such operation is not preferred inasmuch as it might bring excessive pressure to bear at localized positions along (usually to wards the ends of the blades 100 and 102) against the bight portions 136 and 140, which excessive loads might tend to produce undesired results such as blunting the beveled edges of the blades 100 and 102, cutting the bight portions 136 and 140, or imposing stresses on the sections 130 and 132 which might tend to ripple or bend the drive edges 134 and 138 adjacent longitudinal ends of the tool engagement therewith. Also localized engagement of the blades with the bight portions 136 and 140 if asymmetrically applied by the tool engaging elements 70 and 72 might tend to torsionally twist or misalign the parallelism of the edges 104 and 106. In the latter connection, it will be noted that the load carried by the tool on forcible abutment of the posts 60 and 66 are symmetrical and do not produce any such torsional effects.

FIGURE illustrates the relationship of the blades 100 and 102 to the drive edges 134 and 138 when the tool is applied to force the duct work section 130 and 132 into relationship suitable for application of the drive cleat 142, it being noted that the edges 104 and 106 are spaced from the bight portions 136 and 140.

The relationship of the tool 10 to the duct work sections 130 and 132 partially shown in FIGURE 5 is of value in obtaining and understanding of yet another use of the tool 10. Such other use of the tool 10 resides in employing the latter to facilitate removal of a drive cleat from drive edges engaged thereby when disassembling connected sections of duct work. It will be obvious on inspection of FIGURE 5 that the cross section of the blades 100, 102, 112 and 114 corresponds rather faithfully to the cross section of the drive cleat 142 shown in FIG- URE 6. Accordingly, the blades 100, 102, 112 and 114 can be placed in endwise abutting relationship against a drive cleat 142 engaged about the drive edges of duct work sections such as shown in FIGURE 6, whereby the opposite longitudinal end of the work engaging elements 70 and 72 can be struck as with a hammer or the like to drive the drive cleat 142 from its locking position. In this connection, the utility of the stop means comprised of the adjustable screw 60 and the post 66 is much more substantial in that it will be apparent that it is undesirable for the edges 104 and 106 to drag or frictionally engage against the bight portions 136 and 140. Yet, it is also equally desirable that inadvertent opening of the jaws 14 and 16 be avoided. Quite obviously, the stop means limits the approach of the edges 104 and 106 in such a manner that they do not drag against the bight portions 136 and 140 and at the same time enables the toggle link 30 to adequately serve its locking function of holding the jaws 14 and 16 against inadvertent displacement from each other.

In the last discussed use of the tool 10, it will be evident that here again the use of the blades 112 and 114 is not essential, but such use is much preferred for the reason that they bear against an end of the web 144 of the drive cleat 142 so as to lessen the extent to which the inturned legs 146 and 148 must be struck to accomplish a desired endwise movement of the drive cleat 142. Clearly, it is most desirable that the amount of striking against the ends of the legs 146 and 148 should be minimized to avoid upsetting such ends and an even tighter possible wedging of the drive cleat 142 between the drive edges and the main portions of the duct work sections.

While it is especially preferred that the work engaging elements 70 and 72 and the stop means comprised of the threaded post 60 and the abutment post 66 be employed in conjunction with a vice-grip or toggle-type gripping device as hereinabove described, such work engaging elements and stop means can be employed in conjunction with conventional pliers-like tool such as shown in US. Patent No. 1,484,222 which issued to Kightlinger Feb. 19, 1924; US. Patent No. 2,583,896 which issued to Siebrandt Jan. 29, 1952; or US. Patent No. 2,882,768 which issued to Nelson April 21, 1959.

The specifically illustrated embodiment of the invention has been described in elaborate detail for the purpose of conveying a full and complete understanding of the principles involved, and any narrowness in the scope of the invention is not to be thereby implied. Since the illustrated and preferred embodiment of the invention is obviously susceptible to numerous modifications and variations in various details thereof without departing from the spirit of the invention, attention must be directed to the appended claims in order to ascertain the actual scope of the invention.

I claim:

1. In a toggle-type gripping device of the class including pivotally connected jaws having portions constituting coacting work engaging elements, and handles connected by toggle link means for releasably securing the jaws against moving from each other when the jaws are loaded against an object gripped between the work engaging elements; the combination therewith of said jaws being provided with stop means spaced from the portions of the jaws constituting said work engaging elements for positively limiting closure of the jaws to constitute a gripping load for the jaws, whereby the jaws can be releasably secured against movement from each other when the portions of the jaws constituting the work engaging elements are spaced apart.

2. In a toggle-type gripping device of the class including pivotally connected jaws having work engaging elements, and handles connected by a screw adjusted toggle link means for releasably securing the jaws against moving from each other when the jaws are loaded against an object gripped between the jaws; the combination therewith of a stop means threaded through one of said jaws and spaced from the work engaging elements for engaging the other jaw and adjustably limiting movement of the jaws toward each other to constitute a load between the jaws with the work engaging elements in a fixed and spaced relationship predetermined by the adjustment of the stop means.

3. The combination of claim 2, wherein the pivotal connection of the jaws defines a pivotal axis, each of said work engaging elements being elongated in the direction of the pivotal axis and including as a rigid and fixed component thereof a substantially flat blade at its extremity most remote from the pivotal axis that extends toward the blade of the other jaw with said blade terminating in a free edge that is substantially straight and parallel to said pivotal axis, whereby said blades can be engaged under the drive edges of adjacent ducts.

4. The combination of claim 3, wherein the blades are generally fiat, and are substantially coplanar when the spacing of the free edges thereof is approximately equal to twice the thickness of the blades, said blades having planar terminations at the opposite ends of the longitudinal extent of the jaws normal to the pivotal axis, whereby such planar terminations of the blades can abut a drive cleat endwise in driving the latter from engagement with drive edges.

5. The combination of claim 3, wherein each of said jaws includes a second blade spaced from and parallel to the first recited blade, whereby a drive edge can be received therebetween.

6. An improved pliers-like hand tool for use in connection with duct work of the type wherein the drive edges of adjacent sections of duct are secured by a drive cleat, said tool comprising a pair of jaws pivotally connected about a pivotal axis, a pair of handles connected to the jaws for urging the jaws toward each other on manually gripping the handles, each of said jaws being elongated in the direction of the pivotal axis and including a substantially flat blade at its extremity most remote from the pivotal axis that extends toward the blade of the other jaw with said blade terminating in a free edge that is substantially straight and parallel to the pivotal axis, each of said jaws including a second blade spaced from and parallel to the first recited blade, whereby a drive edge can be received therebetween, and stop means carried by one of the jaws in spaced relation to the blades for en- 1 l gaging the other jaw and limiting closure of the jaws to a value such that the free edges of the blades remain spaced.

7. In a toggle-type gripping device of the class including jaws pivotally connected about a pivotal axis and handles connected by a toggle link means that limit forcible closure of the jaws by handles of the device; the combination therewith of said jaws each being elongated in the direction of the pivotal axis and including a substantially fiat blade of substantially uniform thickness at its extremity most remote from the pivotal axis that extends toward the blade of the other jaw with said blade terminating in a free edge that is substantially straight and parallel to the pivotal axis, said blades having ends terminating in planes normal to the pivotal axis, said free edges of the blades being spaced when the jaws are closed to the maximum forcible extent by the handles limited by the toggle link means, each of said jaws including a second 12 blade spaced from and parallel to the first recited blade, whereby a drive edge can be received therebetween, and said second blade having ends terminating in said planes.

References Cited by the Examiner UNITED STATES PATENTS 835,900 11/1906 Casterlin 30193 1,452,372 4/1923 Gomez 8l5.1 1,484,222 2/ 1924 Kightlinger 8l-420 2,253,906 8/1941 Lehman 81-49 2,641,149 6/1953 Petersen 81380 2,731,932 1/1956 Petersen 813 11 2,882,768 4/1959 Nelson 815.1 3,202,023 8/1965 Parker 81-421 WILLIAM FELDMAN, Primary Examiner. G. WEIDENFELD, Assistant Examiner. 

1. IN A TOGGLE-TYPE GRIPPING DEVICE OF THE CLASS INCLUDING PIVOTALLY CONNECTED JAWS HAVING PORTIONS CONSTITUTING COACTING WORK ENGAGING ELEMENTS, AND HANDLES CONNECTED BY TOGGLE LINK MEANS FOR RELEASABLY SECURING THE JAWS AGAINST MOVING FROM EACH OTHER WHEN THE JAWS ARE LOADED AGAINST AN OBJECT GRIPPED BETWEEN THE WORK ENGAGING ELEMENTS; THE COMBINATION THEREWITH OF SAID JAWS BEING PROVIDED WITH STOP MEANS SPACED FROM THE PORTIONS 